Liquid chromatograph detectors heretofore have usually been based on principles of detection that are compatible with the carrier solvent, such as the absorption of ultraviolet or visible light, fluorescence, and changes in refractive index. The detectors, however, have not been found to be compatible with all solvents and have been found to be either of fairly low sensitivity and/or sensitive to only certain types of compounds.
Various other types of detector systems have more recently been developed in an attempt to overcome at least some of these limitations. Of these systems, the so-called transport detectors have been found to present the greatest potential for meeting the needs of modern liquid chromatography, including the detection of polar pesticides.
With respect to the transport detectors, one of the more successful has utilized a disc for transporting the solute to be detected. Disc type transports are shown, for example, in K. Slais and M. Krejci, J. Chromatog. 91, 181(1974); R. P. W. Scott, C. G. Scott, M. Munroe and J. Hess, J. Chromatog. 99, 395 (1974); K. Aitzetmuller, J. Chromatog. Sci. 13, 454 (1975); T. Cotgrave, Chem. Ind. (London), 689 (1966); H. Dubsky, Chem, Listy 67, 533 (1973); E. G. Owens II, H. H. Gill, W. E. Hatton and J. G. Cobler, U.S. Pat. No. 3,376,694 (1968); and H. Dubsky, U.S. Pat. No. 3,744,973 (1973).
Flame ionization detectors have also been heretofore suggested and/or utilized in conjunction with liquid chromatography. Examples of flame ionization detectors are shown in E. Haahit and T. Nikkari, Acta. Chem. Scand. 17, 2565 (1963); J. E. Stouffer, T. E. Kersten and P. M. Krueger, Biochem. Biophys. Acta. 93, 191 (1964); A. Karmen, Anal. Chem. 38, 286 (1966); A. Karmen, Separation Sci. 2, 387 (l967); A. Karmen, Separation Sci. 2, 387 (1967); R. H. Stevens, J. Gas Chromatog. 6, 375 (1968); E. Foster and A. H. Weiss, J. Chromatog. Sci. 9, 266 (1971); S. Lieberman, U.S. Patent No. 3,128,619 (1964); H. W. Johnson Jr., E. E. Seibert and F. H. Stross, Anal. Chem. 40, 403 (1968); A. Karmen, L. D. Kane, M. Karasek and B. Lapidus, J. Chromatog. Sci. 8, 439 (1970); A. A. Balaukin, B. V. Vtorov, V. I. Kalmanovskii and V. P. Chernokozhin, U.S.S.R. Pat. No. 370,520 (1973); C. A. 79 ( 2), 603 (1973); E. G. Owens II, H. H. Gill, W. E. Hatton and J. G. Cobler, U.S. Pat. No. 3,376,694 (1968) and J. J. Szakasits, U.S. Pat. No. 3,788,479 (1974).
Use of a flame ionization detector in conjunction with a disc type transport assembly is shown again by way of example in U.S. Pat. No 3,788,479 (1974).